Is Blue-Green Algae Dangerous for Dogs and Cats?

Blue-green algae (cyanobacteria) are severely toxic to dogs and cats. Exposure to this bacterium often results in death. It is strongly recommended to stay clear of all infected bodies of water.

What are blue-green algae?

Blue-green algae, also known as cyanobacteria, are bacteria found in lakes, ponds, brackish water, streams, and sometimes saltwater. The blue-green algae bloom and resemble green paint floating on the surface of the water. Although not all blooms contain toxins, it is not possible to know without proper testing. Thus, it is recommended to avoid all bodies of water where blue-green algae have bloomed.

How are dogs, cats and people exposed to blue-green algae?

These bacteria can produce toxins that are harmful to pets and people who inhale or drink from infected bodies of water, or swim in them during these activities:

• Swimming, boating, or fishing in areas with noticeable blue-green algae blooms.
• Eating fish caught from areas with noticeable blue-green algae blooms.
• Household use (bathing, showering, and washing dishes) of untreated and in-home-treated surface waters when there is a bloom.
• Drinking, preparing food, cooking, and making ice with water containing blue-green algae or their toxins. ¹

What are the common signs of exposure to blue-green algae in dogs and cats?

The following signs of poisoning can begin anywhere from 15 minutes to several days after exposure to the blue-green algae:

• Vomiting
• Diarrhea
• Blood in stool
• Black or tarry stool
• Weakness
• Pale mucous membranes
• Jaundice
• Liver Damage/Failure
• Tremors
• Seizures
• Disorientation
• Coma
• Muscle rigidity
• Paralysis
• Blue discoloration of the skin and mucous membranes (Cyanosis)
• Difficulty breathing
• Death² 

What to do if my dog or cat has been exposed to blue-green algae?

If you suspect your dog or cat has come into contact with blue-green algae, immediate intervention is critical. Contact your veterinarian or the poison control centre immediately.

Sources:

¹ https://www.health.ny.gov/environmental/water/drinking/bluegreenalgae/blue-green_algae_advice.htm

² https://www.petpoisonhelpline.com/poison/blue-green-algae/